Case study: Myths of transfusion medicine (Part one of a two-part series)

transfusion medicine

Myth 1: You can’t give dogs blood to cats

The first reported xenotransfusions—transfusions between different species—were performed by Jean-Baptiste Denis in 1667 where calf blood was administered to dogs; thereafter, he transfused blood from a lamb to a young man, curing him of a high fever. He wrote: ‘‘Great advantages will follow upon the mixture of different bloods’’ and ‘‘the blood of animals is less full of impurities than that of men because debauchery and irregularity in eating and drinking are not so common in them as in us.’’ (Roux 2007)

Several recent studies have described the use of dog blood for transfusion to cats in situations where type compatible feline blood was not available. A 2013 literature review in J Feline Med Surg described 62 cats receiving dog blood (From 1962 to 2004). While no severe acute reactions were seen, the life span of the red blood cells was less than four days. Nine cats receiving dog blood products were described in a separate report (IVECCS 2015). The eight cats receiving red cell products all had an increase in PCV and the one cat receiving FFP had improvement in both albumin and clotting times. Severe hemoglobinuria was seen in one cat. A 2016 report of two cats receiving dog red blood cells confirmed that all the red cells were destroyed within four days. (Euler 2016).

However, a 2017 study published in JVECSS by Priolo et al. reported significant incompatibilities detected by cross-match tests between feline and canine blood prior to any transfusions. Blood samples from 34 cats and 42 dogs were used to perform test tube major and minor cross-match tests and blood typing. Blood from each cat was cross matched with blood from 2–6 dogs, for a total of 111 crossmatch tests.

Eighty-three overall major cross-match tests were positive at 37°C, 86 at room temperature and 90 at 4°C. The minor cross-match tests were positive in all but two cross-matches performed at 37°C, all tests performed at room temperature and all but one test performed at 4°C. No cats tested totally negative at both major and minor cross-matches performed with samples from any single dog.

This study reveals a high prevalence of naturally occurring antibodies in cats against dog erythrocyte antigens and vice versa, and suggests that transfusion of cats with canine blood is not recommended as a routine procedure due to the potential high risk of either acute, severe or milder transfusion reactions. It is possible that some transfusion reactions weren’t noted in earlier studies due to cruder monitoring techniques. At VSS we have had one acute severe anaphylaxis in a cat who had never received dog blood products previously.

Xenotransfusions should only be considered in exceptional/emergency circumstances (e.g. imminent cardiopulmonary arrest due to blood loss or anaemia, inability to source/collect feline blood, rare Type B blood type), remembering that the life span of the transfused canine RBCs is very short (3-5 days) and marked RBC haemolysis and icterus ensues.

Clinically we try and only administer packed red blood cells (PRBCs) to avoid any minor incompatibilities of the donor serum with recipient RBCs. ~25ml PRBCs per cat seems to increase the PCV from a single digit or low teens to higher teens/low 20s. We give enough to get the cat clinically stable and don’t transfuse to a ‘normal’ PCV as the donated RBCs will be haemolysed in coming days. Whole blood can also be administered, taking care with volume overload in chronically anaemic cats. ~50ml whole blood per cat.

Myth 2: X-matches for first time transfusions are not needed. 

Feline evidence

A retrospective study looking at feline packed red blood cell transfusions showed a higher increase in PCV in those transfusion where a cross match was performed. A recent study of cross matching in cats demonstrated that 25% of cats developed alloantibodies to antigens outside of the AB system within 2–10 days of a blood transfusion. A second study presented in abstract form at ACVIM 2018 reported that 15% of cats who had never received a transfusion were incompatible to one or more donors and 27% were incompatible by the second transfusion. Based on these studies, cross matching is recommended before all feline red cell transfusions. Cross matching can be performed using a manual procedure or using a commercial gel cross match.

Canine Evidence:

A 2017 article published in JAVMA looked at 149 major cross matches in dogs admitted to a veterinary teaching hospital with no history of prior red blood cell transfusions. Results: 25 of 149 (17%) dogs evaluated by crossmatching were incompatible with one or two of the three potential donors. All 149 dogs were compatible with ≥ 1 potential donor. Mean ± SD change in Hct after transfusion was significantly higher in dogs that had cross matching performed (12.5 ± 8.6%) than in dogs that did not undergo cross matching (9.0 ± 4.3%).

Results indicated immunologic incompatibility can exist between first-time transfusion recipients and potential blood donor dogs. The clinical importance of these findings could not be evaluated, but considering the potential for immediate or delayed haemolytic transfusion reactions or shortened RBC life span, the authors suggest veterinarians consider cross matching all dogs prior to transfusion when possible.

Myth 3: Hartmann’s solution is incompatible with blood products

Crystalloid fluids and red-cell-containing blood products are commonly used for resuscitation of patients in hemorrhagic shock. However, current transfusion guidelines advise against co-administration of red-blood-cell containing products with Lactated Ringers (LRS – equivalent to Hartmans) because of the potential for clot formation, potentially leading to negative patient outcomes. The evidence supporting these guidelines is conflicting. Original studies conducted in the 1970s and 80s demonstrated the potential for small amounts of calcium in LRS to overwhelm anticoagulants in whole blood for transfusion, resulting in clot formation at higher LRS-to-blood product ratios. Research published since 2000 has suggested that certain blood product additives, saline-adenine-glucose mannitol (SAGM) and rapid transfusion methods currently in use may reduce the potential for LRS to induce coagulation. A systematic review of the available literature is necessary to summarise the evidence in a methodologically rigorous manner.

A 2010 study published in the Canadian Journal of Anaesthesia found that LRS is compatible with SAGM preserved packed red blood cells for rapid transfusion. No clotting was detected at any dilution of LRS with SAGM- preserved PRBC within 60 min, but clotting was detected with extended incubation. The results indicate Ringers Lactate can be safely co-administered with PRBC during rapid transfusion.


Bovens C, Gruffydd-Jones T (2013) Xenotransfusion with canine blood in the feline species: review of the literature. J Feline Med Surg 15, 62–67.

Roux FA, Sai P, Deschamps JY (2007) Xenotransfusion, past and present.

Xenotransplantation 14, 208–216.

Cooper DK (2003) Porcine red blood cells as a source of blood transfusion in humans. Xenotransplantation 10, 384–386.

Weltman JG, Fletcher DJ, Rogers D. Influence of cross-match on posttransfusion packed cell volume in feline packed red blood cell transfusion. JVECCS. 24(4) 2014, pp 429–436

Hourani L, Weingart C, Kohn B. Alloimmunisation in transfused patients; serial cross-matching in a population of hospitalized cats. J Feline Med Surg. 2017;19(12):1231–1237.

Klaser DA, Reine NJ, Hohenhaus AE. Red blood cell transfusion in cats: 126 cases (1999). J Am Vet Med Assoc. 2005;226(6):920–923.

McClosky ME, Brown DC, Weinstein N, et al. Prevalence of naturally occurring non-AB red blood cell alloantibodies in cats. In: Proceedings of the American College of Veterinary Internal Medicine; 2018: Seattle.

Odunayo A, et al. Incidence of incompatible crossmatch results in dogs admitted to a veterinary teaching hospital with no history of prior red blood cell transfusion. J Am Vet Med Assoc. 2017 Feb 1;250(3):303-308.

Higgs VA, et al. Autologous blood transfusion in dogs with thoracic or abdominal hemorrhage: 25 cases (2007–2012). Journal of Veterinary Emergency and Critical Care. 2015, 25(6), pp 731–738


transfusion medicine

Dr Ellie Leister is the Pet Intensive Care Unit Veterinary Manager at Veterinary Specialist Services in Brisbane.

In 2004, Dr Leister spent four years in mixed practice in country NSW before sitting memberships and moving to England where she started to focus more on small animals and her passion for emergency and critical care started

Dr Leister has worked exclusively as a critical care veterinarian in the Pet Intensive Care Unit at VSS in Brisbane since returning in 2012. She manages a team of 20 people and the ICU operates 24/7.

The PICU is known nationally a one of the most well run and busiest critical care centers in the country. It manages very complex cardiology, oncology, medical and surgical cases as well as everyday emergencies.


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